Preserve URL Extensions with Jekyll

jekyll comments edit

In my last post I wrote about migrating my blog to Jekyll and GitHub Pages. Travis Illig, a long time Subtext user asked me the following question:

The only thing I haven't really figured out is how to nicely handle the redirect from old URLs (/archive/blah/something.aspx) to the new ones without extensions (/archive/blah/something/). I've seen some meta redirect stuff combined with JavaScript but... UGH.

UGH Indeed! I decided not to bother with changing my existing URLs to be extensionless. Instead, I focused on preserving my existing permalinks by structuring my posts such that they preserved their existing URLs.

How did I do this? My old URLs have an ASP.NET .aspx extension. Surely, GitHub Pages won't serve up ASPX files. This is true. But what it will serve up is a folder that just happens to have a name that ends with ".aspx".

The trick is in how I named the markdown files for my old posts. For example, check out a recent post: 2013-11-20-declare-dont-tell.aspx.markdown

Jekyll takes the part after the date and before the .markdown extension and uses that as the post's URL slug. In this case, the "slug" is declare-dont-tell.aspx.

The way it handles extensionless URLs is to create a folder with the slug name (in this case a folder named declare-dont-tell.aspx) and creates the blog post as a file named index.html in that folder. Simple.

Thus the URL for that blog post is http://haacked.com/archive/2013/11/20/declare-dont-tell.aspx/. But here's the beautiful part. GitHub Pages doesn't require that trailing slash. So if you make a request for http://haacked.com/archive/2013/11/20/declare-dont-tell.aspx, everything still works! GitHub simply redirects you to the version with the trailing slash.

Meanwhile, all my new posts from this point on will have a nice clean extensionless slug without breaking any permalinks for my old posts.

Comments